A method can include receiving block position data of a rig prior to addition of a length of pipe to a drillstring, where the drillstring is disposed at least in part in a borehole and supported by the rig; receiving block position data of the rig after addition of the length of pipe to the drillstring; and controlling position of the drillstring with respect to time using the rig and at least a portion of the block position data for landing a drill bit of the drillstring on a bottom of the borehole.

Downhole tractor control systems and methods to maintain a load of a downhole tractor are disclosed. A method to maintain a load of a downhole tractor includes identifying a reduction of power of a first set of motors of a plurality of motors of the downhole tractor, determining whether the reduction of power of the first set of motors is below a first threshold, and increasing, in response to the determination, a first power limit of a second set of motors of the plurality of motors to a maximum acceptable power limit of the second set of motors while maintaining the load of the downhole tractor.

Downhole tractor control systems and methods to maintain a load of a downhole tractor are disclosed. A method to maintain a load of a downhole tractor includes identifying a reduction of power of a first set of motors of a plurality of motors of the downhole tractor, determining whether the reduction of power of the first set of motors is below a first threshold, and increasing, in response to the determination, a first power limit of a second set of motors of the plurality of motors to a maximum acceptable power limit of the second set of motors while maintaining the load of the downhole tractor.

A method can include receiving input for a drilling operation that utilizes a bottom hole assembly and drilling fluid; generating a set of offset drilling operations using historical feature data, where the historical feature data are processed by computing feature distances; performing an assessment of the offset drilling operations as characterized by at least feature distance-based similarity between the drilling operation and the offset drilling operations; and outputting at least one recommendation for selection of one or more of a component of the bottom hole assembly and the drilling fluid based on the assessment.

A method can include receiving input for a drilling operation that utilizes a bottom hole assembly and drilling fluid; generating a set of offset drilling operations using historical feature data, where the historical feature data are processed by computing feature distances; performing an assessment of the offset drilling operations as characterized by at least feature distance-based similarity between the drilling operation and the offset drilling operations; and outputting at least one recommendation for selection of one or more of a component of the bottom hole assembly and the drilling fluid based on the assessment.

Techniques according to the present disclosure include moving an untethered downhole tool through a wellbore between a terranean surface and a particular depth in the wellbore; during the moving the untethered downhole tool through the wellbore, acquiring a set of sensed data from one or more sensors in the untethered downhole tool in a time domain; transforming the plurality of data values associated with the wellbore parameter in the time-domain into a plurality of data values associated with the wellbore parameter in a depth-domain based at least in part on at least one accelerometer output and the locations of a plurality of casing collars; and preparing the plurality of data values associated with the wellbore parameter in the depth-domain for presentation on a graphical user interface (GUI).

Downhole tractor control systems and methods to maintain a load among multiple tractors are disclosed. A method to adjust a load among multiple tractors includes receiving first power feedback of a first downhole tractor, receiving second power feedback of a second downhole tractor, identifying an unbalance load condition when a difference between the first power feedback and the second power feedback exceeds a predetermined threshold, and adjusting, in response to identifying the unbalance load condition and based on the difference, power reference of the first downhole tractor and the second downhole tractor.

At least one non-transitory computer readable medium storing instructions that when run on at least one processor of a surface computer system of a measurement while drilling (MWD) system of a drilling rig, causes the surface computer system to: receive a first data stream by a mud pulse telemetry receiver of the surface computer system, detect a synchronization signal indicative of an interruption of transmission of the first data stream due to occurrence of a predetermined event at an unexpected time, and synchronizing the mud pulse telemetry receiver with the synchronization signal; and receive a second data stream by the mud pulse telemetry receiver, in which the second data stream has at least one group of data including drilling logging data.

At least one non-transitory computer readable medium storing instructions that when run on at least one processor of a surface computer system of a measurement while drilling (MWD) system of a drilling rig, causes the surface computer system to: receive a first data stream by a mud pulse telemetry receiver of the surface computer system, detect a synchronization signal indicative of an interruption of transmission of the first data stream due to occurrence of a predetermined event at an unexpected time, and synchronizing the mud pulse telemetry receiver with the synchronization signal; and receive a second data stream by the mud pulse telemetry receiver, in which the second data stream has at least one group of data including drilling logging data.

Apparatus, systems, and methods for ranging operate to use a wireline active ranging system to initially determine a relative distance and relative direction from a first well (e.g., ranging well) to a second well (e.g., target well) and an EM azimuthal logging tool to maintain or adjust the distance from the target well while drilling the ranging well. Additional apparatus, systems, and methods are disclosed.